HOLYOKE - Every Sunday as a boy, Gerardo Ramos would watch ocean-explorer Jacques Cousteau on television. And then, with the deep sea swirling through his imagination, he would go diving.

He would go diving with his father. His father taught him how to snorkel and, later how, to use an oxygen tank. His father taught him how to spear a fish and how to catch a lobster by hand.

His father guided him through slippery underwater flora and over pulsating coral reefs.

"As a teenager, I found refuge in the ocean," says the now-35-year-old Holyoke resident.

Yet, newly-wed and around 19, Ramos left behind his home in Guayama, Puerto Rico for Western Massachusetts. "And, here I was, in the urban jungle - lost," he recalled recently of those early years away from home.

So, with the ocean more than two hours down the Massachusetts Turnpike, Ramos had an idea: He would bring the sea to the urban jungle.

And ever since, that ocean of his making has been multiplying, expanding and branching out.

Drive too fast, and you'll miss it. Ramos owns Marine Reef Habitat, an aquarium - or "a handmade laboratory," as he calls it - located in a tiny greenhouse in the heart of South Holyoke on the corner of Main and Cabot streets.

Starting in his home, Ramos grows ocean coral, housing 68 species in the glass-encased space attached to the main offices of Nuestras Raices, a community gardening and agricultural organization.

He sells tropical coral and fish for personal, educational and scientific use, and he installs and maintains home saltwater fish tanks. He also provides a sort of marine-biology center for area youth, whom he provides with free tanks.

"I have one kid who is a genius," Ramos said of a 14-year-old who took a tank home and started growing his own coral. "He has the most beautiful reef."

As he spoke, Ramos, neatly dressed in a white short-sleeve dress shirt and gray slacks, repeatedly reached into a 90-gallon wood-framed tank. The tank, along with much of the rest of the aquarium, is made of other people's scraps.

A blue barrel used for filtration came from a construction site. Ramos took PVC pipes from roadside trash heaps. Much of the rest, including Plexiglas for the tanks, was donated.

"I decided this is what I am going to do for the rest of my life," Ramos said as he took out examples of one species after another, speaking passionately about each.

Ramos has big ambitions - starting with his home in Puerto Rico. About six years ago, he returned and was shocked.

"The whole reef was depleted and dead," he said. Coral reefs are dying out around the world from pollution, possibly global warming and people hacking off chunks to sell for home aquariums, he explained.

Eventually, Ramos wants to use the coral he's producing to repopulate the reefs of his home. "Without the ocean, we would not be here, and we are depleting it. I want to put a grain back in," he said.

But first, he needs to move the operation. The current spot, he said, is too small and polluted from traffic, as seen in streaks of black soot from truck fumes on the walls, blown in through vents.

He plans to relocate to the Nuestras Raices farm off Jones Ferry Road. A greenhouse is now being built, he said.

He also hopes to receive loans or grants to buy much-needed new equipment.

But most importantly, Ramos hopes to continue to be source of education for curious youth.

Before Ramos finished speaking, one young person opened a door and walked into the greenhouse. Ramos asked what he could do for the young man.

"I've been seeing this place forever," he said, "and I wanted to know if you could use any help."